Re: 640x512x16bpp with VESA ?

Hi, and thanks again for the interesting hints :-)

I've read again more closely the vbe3.pdf
and updated my VBE probe software, but i have not
yet tested it. Sometimes, i have to sleep :-)

Dirk Wolfgang Glomp wrote:
INT 10 - VESA SuperVGA BIOS - SET SuperVGA VIDEO MODE
Videomode + 800h = use refresh rate control(only VBE3)
hmmmm sounds interesting, but i don't know what it is.
This part can be used to set a vesamode with own CRTC-Values.

Re-reading vbe3.pdf, it is not clear which mode number
i should setup : because the resolution i want is not listed,
i can't ask an existing mode. It is not clear if i can ask
"any" VBE mode and just throw my own CRTInfoBlock.

Usefull to initialize a higher refreshrate as the custom 60hz.
The first step is to store CRTC-values in a table.
The second step ist to to get the exact pixel clock for the hardware.
And now the refreshrate can be recalculate.

wow, that's scary, and i thought that programming the 6845 was difficult :-)

I have found the following on Google while searching the "640x512" string :
(**) TDFX(0): *Default mode "640x512": 54.0 MHz, 64.0 kHz, 60.0 Hz (D)
(II) TDFX(0): Modeline "640x512" 54.00 640 664 720 844 512 512 514 533 doublescan +hsync +vsync
ah
maybe that's compatible with the CRTInfoBlock, if X.org goes through VBE (which is probable)


thanks for the tables, but i see no 5:4 aspect ratio mode,
except the 1280x1024 mode :-/

;--------------------------------------
; VBEHZ = 1280x1024@120Hz
;--------------------------------------
HORTOTA DW 1728
HORISTA DW 1352
HORIEND DW 1504
VERTOTA DW 1066
VERTSTA DW 1025
VERTEND DW 1028
DOIFLAG DB 00h
PIXCLOC DD 221045760
REFRATE DW 12000
DB 40 dup (0)
;--------------------------------------

thanks again but that is not the 640x512 mode :-)
but i can start from there and tweak progressively ...

thanks again,

Dirk
YG

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